Context learning and the effect of context on memory retrieval in Lymnaea

Aerial respiratory behavior in Lymnaea was operantly conditioned so that th e animals perform aerial respiration significantly less often. Using the st andard training procedure (pond water made hypoxic by bubbling N-2 through it) both food-deprived and fed animals learned and exhibited long-term memo ry (LTM). However, food-deprived animals exhibited neither learning nor mem ory when trained under a condition in which the hypoxic pond water also con tained a food odorant (carrot, the food-odorant procedure). Fed animals, ho wever, learned and exhibited LTM with the food-odorant procedure. Thus, the presence of the food odorant per se did not prevent learning or the establ ishment of LTM. Further experimentation, however, revealed that the ability of the snails to have recall (i.e., memory) for the learned behavior was d ependent on the context in which memory was tested. That is, if animals wer e trained with the food-odorant procedure they could only exhibit recall if tested in the food-odorant context and vice versa with the standard traini ng procedure. Thus, although fed animals could learn and show LTM with eith er training and testing procedure, LTM could only be seen when they were te sted in the context in which the) were trained.